Simple ray-face intersect optimization

I was looking for ways to handle ray-face intersections on the web, everyone talks about using a ray to do the test, but none suggested using a plane instead.

Here's a simple optimization on ray-face intersection that may speedup your model picking or intersection test.

any implementation of ray-face intersect would have to determine if the intersection point with a face is within the face bounds.
By using a plane instead of a ray you can cut down the number of face-ray overlap or intersection tests, only the faces with points on both sides of the cutting plane are consider see diagram.

I have not tested how fast it could be using the plane versus the ray, but I bet the dot products should be faster than getting the intersection points, or testing for ray-face overlap specially when dealing with high number of faces like in a mesh.

Oh, I understand; you aren't optimizing the ray-face intersection per se, you're optimizing how to find the face itself.

I'm not so sure this will make it all that much faster; I think a kd-tree would be better suited for the task. Instead of checking all those faces for plane intersection, you just check the tree to see if the ray intersects with the box that contains the face.

Kd-trees are almost universally accepted as the fastest tree-method [citation needed], and are pretty much the de-facto standard in raytracers. I don't really have much experience with them out of raytracing, so I can't say (for sure) that it's the same way in games. However, I'm pretty certain.